Paclitaxel-Coated Balloon for the Treatment of Multilayer In-Stent Restenosis: AGENT IDE Subgroup Analysis

Background: Patients with coronary in-stent restenosis (ISR) within multiple layers of stent pose a specific clinical challenge because of higher rates of recurrent restenosis as well as a desire to avoid an additional layer of stent. Drug-coated balloons (DCBs) provide an alternative antiproliferative therapeutic option for multilayer ISR. Objectives: We evaluated the efficacy and safety of a low-dose paclitaxel-coated vs uncoated balloon among patients with multilayer or single-layer ISR in the AGENT IDE (A Clinical Trial to Assess the Agent Paclitaxel Coated PTCA Balloon Catheter for the Treatment of Subjects With In-Stent Restenosis) trial. Methods: AGENT IDE is a prospective, multicenter trial that randomized patients with ISR (reference vessel diameter >2.0 mm to ≤4.0 mm and lesion length <26 mm) in a 2:1 allocation to paclitaxel-coated or an uncoated balloon following successful lesion preparation. Randomization was stratified by multi- vs single-layer ISR as well as by center. The primary study endpoint was 1-year target lesion failure (TLF): composite occurrence of ischemia-driven target lesion revascularization (TLR), target vessel-related myocardial infarction (MI), or cardiac death. Results: Of the 600 patients randomized in the trial, multilayer ISR was present in 258 (44%) patients. Patients with multilayer ISR had higher rates of TLF at 1 year compared with those with single-layer ISR (29.0% vs 15.7%, P < 0.0001). The overall study results were consistent irrespective of multilayer vs single-layer ISR (P_interaction = 0.66). Among patients with multilayer ISR, TLF was lower with paclitaxel-coated balloon compared with an uncoated balloon (23.8% vs 40.0%; HR: 0.55; 95% CI: 0.34-0.87; P = 0.01), driven by reductions in both TLR and target vessel-related MI. Similar findings were observed among patients with single layer ISR (1-year TLF: 13.5% with paclitaxel-coated vs 20.2% with uncoated balloon; HR: 0.64; 95% CI: 0.37-1.11; P = 0.11), although absolute event rates were lower. Conclusions: Patients with ISR of multiple stent layers had higher rates of adverse stent-related events compared with patients with single-layer ISR. Treatment with a paclitaxel-coated balloon led to greater absolute risk reduction in 1-year TLF among patients with multilayer ISR compared with an uncoated balloon.